A shackle has to provide the security of connection between two parts.
Its choice cannot be haphazard. Shackles available are made out of
stainless steel and are designed hold and withstand the elements. Install
one of these shackles that have a larger opening for the halyards or
other connections you need to makeon your boat.

Open shackles have a similar shape to "D" shackles but are proportionally wider for their length. They have a smaller maximum working load due to the long pin length. Because of this, it is especially important to consider the loads involved in your application when using a large open shackle.

About Harken Large Open Shackles
The stainless steel Large Open Shackles wich Harken uses on Harken blocks are available separately.Harken large open shackles are made from forged stainless steel and polished to a shine. Harken has recently increased it's rage of shackles in both the number of configurations and sizes available. The Harken 5mm Open Shackle has a shackle pin diameter of 3/16 inches or 5 millimeters. They have a length of 1 5/16" or 33mm and a overall width of 13/16" or 20mm. Harken 5mm Open Shackles weigh 0.88 oz or 25 grams.

The maximum working load on the Harken 5mm large open stainless steel shackle is 770 pounds which is 350 kilograms. The Breaking load is 2200 pounds or 1000 kilograms. The breaking strength on the Harken Large Open Stainless Steel Shackle is derived from tests that support 80% of the length of the screw pin that is unsupported, which is similar to the area of a post in a block. Safe working loads are no more than half the minimum breaking strength.

About Wichard Self-Locking Large Opening Shackles
Wichard Open Shackles are constructed from forged stainless steel and are designed and made in France. They feature a self locking pinthat is designed for your safety. Small indentations in the wichard open shackle engage the head of the pin. When the user applies a final tightening tension is created that locks the pin in place. Even the most violent vibrations will not loosen the pin which helps avoid accidental release that is possible with other shackles. Wichard Open shacles are available in four different sizes.

The sizing of open shackes is based primarily on the pin size but it is important to also check the other dimensions to ensure a proper fit for yout application. All dimensions, including working loads, breaking loads and weights can be found on the Wichard Large Open Shackle page linked to above.

We at Mauri Pro Sailing are fully committed to be your Open Shackle specialist not only providing the sailing community with a comprehensive and easy to use web site but with all the appropriate technical information that you might need to select your sailboat hardware and equipment. If you need any assistance selecting the appropriate Large Open Shackle for your boat or application please contact us. Our crew is ready to help!